From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 5 Jun 2002 08:18:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 5 Jun 2002 08:18:20 -0400 Received: from mailout02.sul.t-online.com ([194.25.134.17]:34776 "EHLO mailout02.sul.t-online.com") by vger.kernel.org with ESMTP id ; Wed, 5 Jun 2002 08:18:20 -0400 Date: Wed, 5 Jun 2002 14:17:55 +0200 From: Andi Kleen To: Ian Collinson Cc: "'Andrew Morton'" , Robert Love , Andi Kleen , Mike Kravetz , linux-kernel@vger.kernel.org, andrea@suse.de Subject: Re: realtime scheduling problems with 2.4 linux kernel >= 2.4.10 Message-ID: <20020605141755.A1410@averell> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.22.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 05, 2002 at 01:53:06PM +0200, Ian Collinson wrote: > > Are there any potentially negative consequences of this fix, apart from > those already mentioned? I don't think so. It could still fail when you install a prio=99, SCHED_FIFO process. > I certainly vote for this feature being preserved, as it is extremely useful > for debugging realtime priority apps. FYI, we narrowed it down to breaking > in either 2.4.10-pre11 or pre12. That was when the low latency console changes went in. Before that console switches could interrupt scheduling for a long time, causing problems for other realtime people. The change was to move the expensive parts of the console switch to keventd. -Andi